Post on 05-Feb-2023
www.elsevier.com/locate/tecto
Tectonophysics 398 (
The tectonic frame of the Variscan–Alleghanian orogen in Southern
Europe and Northern Africa
J. Fernando Simancasa, Abdelfatah Tahirib, Antonio Azora,T,Francisco Gonzalez Lodeiroa, David J. Martınez Poyatosa, Hassan El Hadic
aDepartamento de Geodinamica, Facultad de Ciencias, Campus de Fuentenueva, Universidad de Granada, Granada 18071, SpainbInstitut Scientifique, BP 703, Rabat-Agdal, Morocco
cFaculte des Sciences Ben Msik-Sidi Othmane, Casablanca, Morocco
Received 26 July 2004; received in revised form 16 February 2005; accepted 21 February 2005
Available online 19 March 2005
Abstract
By confronting different geological and geophysical data, we attempt to reconstruct the Variscan–Alleghanian orogenic belt,
with especial emphasis on the links between Iberia, northwest Africa, and northeast America.
The northern Iberia transect corresponds to the rifted margin of Gondwana, inverted during the Variscan orogeny and
overthrust in its westernmost sector by a pile of allochthonous units, some of them with oceanic affinity and witnessing an
orogenic suture. The southern Iberia section reveals two sutures at both boundaries of a terrane closely tied to Gondwana,
namely the Ossa–Morena Zone. The southern boundary of this zone (i.e., the contact with the South Portuguese Zone) is
enhanced by amphibolites with oceanic affinity and probably represents the suture of the Rheic Ocean.
The Moroccan Variscides can be divided into: (i) a western external zone, namely the Coastal Block and the Central Massif;
(ii) an internal zone, namely the Eastern Meseta; (iii) an eastern external zone represented in the Anti Atlas region; and (iv) the
African cratonic foreland. Since neither ophiolites nor eclogites crop out along this transect of the orogen, we consider it to be
an incomplete transect, lacking the main suture zone (Rheic Ocean).
Stratigraphic and faunal affinities between the Moroccan Meseta, on the one hand, and the Central Iberian, Western
Asturian–Leonese, and Cantabrian zones of Iberia, on the other hand, suggest that they may well have been part of a common
pre-orogenic domain at the margin of Gondwana. On the contrary, there are no counterparts in Morocco for the Ossa–Morena
Zone. Thus, the northern Iberia palaeogeographic zones would prolong in the Moroccan Meseta through an eastward arcuate
structure, while the suture of the Rheic Ocean would do so offshore Morocco. In our reconstruction, an Avalonian spur (Grand
Banks indentor), which included the Caledonian Sehoul block in northern Morocco and the crust of the South Portuguese Zone
in SW Iberia, played an important role on the kinematic evolution of the orogen as well as on the final configuration of the
0040-1951/$ - s
doi:10.1016/j.tec
T Correspondi
E-mail addr
2005) 181–198
ee front matter D 2005 Elsevier B.V. All rights reserved.
to.2005.02.006
ng author. Tel.: +34 958 242900; fax: +34 958 248527.
ess: azor@ugr.es (A. Azor).
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198182
suture of the Rheic Ocean. This suture would mould around the Avalonian spur, being laterally translated to southeastern Nova
Scotia–Newfoundland.
D 2005 Elsevier B.V. All rights reserved.
Keywords: Rheic Ocean; Orogenic sutures; Gondwana; Avalonia; Moroccan Meseta; Iberian Massif; Variscan orogen
1. Introduction and fundamentals
The outcrops of the Variscan–Alleghanian Late
Palaeozoic orogenic belt are dispersed in western
Europe, northwest Africa and northeast America, due
to both the opening of the Atlantic ocean and the
Alpine tectonics around the Mediterranean. Moreover,
despite the important advance on the knowledge of
the different outcrops of this orogen in recent years,
there still remains some uncertainty as to the position
and number of oceanic domains as well as the linkage
between the different palaeogeographic zones. For
these reasons, the reconstruction of this orogen at pre-
collisional and collisional stages is a rather compli-
cated task, requiring a vast amount of geological and
geophysical data.
The purpose of this paper is to briefly review the
main features of the Variscan–Alleghanian orogen in
its central segment, in order to propose a comprehen-
sive view of its tectonic frame. The main problem
hindering this reconstruction has traditionally been the
tectonic Variscan linkage of Iberia with northwest
Africa and northeast America. Our present-day geo-
logical knowledge enables us to propose a reasonably
well-based tectonic picture.
The tectonic frame that we put forward in this
paper is based on a model of Palaeozoic dispersal
and aggregation of continents, which serves as a
template for our more detailed account. This model
arises out of a close scrutiny of geological (main
tectonic boundaries), palaeontological (faunal affin-
ities), and palaeomagnetic data (palaeolatitude of
continental masses), trying to determine the point
of convergence among these three different types of
evidence. This attempt is subject to a number of
shortcomings, especially the fact that palaeomagnetic
models still conflict in some important points with
geological and palaeontological data. Thus, different
sets of data fit in well within a general model of
Cambrian to Ordovician palaeogeography (Crowley
et al., 2000a; Nys&ther et al., 2002), but for
Devonian time, palaeomagnetic reconstructions show
a large ocean between Gondwana and Laurentia/
Baltica (Torsvik et al., 1990; Tait et al., 1997), which
is largely incompatible with palaeontological evi-
dence (McKerrow et al., 2000; Robardet, 2003). The
general model of continental dispersal and aggrega-
tion assumed here as a starting point is very close to
the one proposed by Matte (2001), which includes:
a) a Cambrian to Ordovician breaking of the
Gondwana margin to form an independent, perhaps
composite, continental mass (Avalonia) that drifted
away until its Ordovician to Devonian complex
collision with Laurentia/Baltica (Caledonian/Taconic
and Acadian orogenic events); b) an additional
Ordovician breaking of the Gondwana margin
originating a number of terranes which, unlike
Avalonia, remained closely tied to Gondwana (Kem-
nitz et al., 2002; Nys&ther et al., 2002); c) a
contemporaneous development of continental gra-
bens/rifts along the margin of Gondwana; d) the
formation of an Ordovician–Silurian ocean (the Rheic
Ocean) between the wandering Avalonia and the
Gondwana-related terranes; e) the closing of the
Rheic Ocean in Devonian time and welding of the
terranes around Gondwana (early Variscan orogenic
events); and f) a Carboniferous collision of Avalonia,
Gondwana, and the terranes in between (Variscan/
Alleghanian orogenic events).
2. The Variscan tectonic organization in Iberia
The Alpine reworking is intense in the eastern
areas of the Iberian Peninsula (Betic ranges, Pyrenees)
but relatively weak in most of the so-called Iberian
Massif, which is the largest continuous outcrop of the
Variscan Belt (Fig. 1A and B). The Variscan tectonic
organization of the Iberian Massif is better understood
in terms of considering two different geological
Fig. 1. (A) Location of Iberia in the Alleghanian–Variscan Orogenic belt. (B) Variscan tectonic zones in the Iberian Massif. C1 and C2: northern
(Perez Estaun et al., 1991) and southern (Simancas et al., 2001) cross-sections of the Iberian Massif. Note that the patterns are different in the
Iberian map and the cross-sections.
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198 183
transects: the northern Iberia transect and the southern
Iberia transect (Fig. 1B).
In northern Iberia, the orogenic vergence is towards
the east. From west to east, this transect is made up of
the following tectonometamorphic domains (Fig. 1B
and C1): a) an internal zone with allochthonous units
of continental and oceanic terranes, some of them
having undergone granulitic and eclogitic metamor-
phism (Arenas et al., 1986; Martınez Catalan et al.,
1996); b) an intermediate domain composed of schists
intruded by some granites (western part) and slates
(eastern part), deformed by east-vergent kilometer-
scale recumbent folds and thrusts (Martınez Catalan et
al., 1990); and c) an external zone consisting in a non-
metamorphic thin-skinned thrust belt, with Lower
Palaeozoic shelf sediments and a thick pile of Lower
to Upper Carboniferous synorogenic deposits (Perez
Estaun and Bastida, 1990). Leaving aside some
Caledonian ages recorded only in the uppermost
allochthonous units (Abati et al., 1999; Fernandez-
Suarez et al., 2002), the age of the first tectonome-
tamorphic events is Early Devonian in the allochth-
onous units. Deformation migrated eastward, reaching
the easternmost units in Westphalian times. Thus, the
northern Iberia section shows a complete orogenic
wedge from allochtonous suture terranes in the west to
a foreland fold-and-thrust belt in the east (Perez
Estaun et al., 1991; Dallmeyer et al., 1997). The
Early Palaeozoic palaeogeography of the Gondwana
border (before the orogenic events) was, from west to
east: (i) a passive continental margin (represented by
the lower units of the allochthonous Galicia Tras-os-
Montes Zone; Martınez Catalan et al., 1996); (ii) an
internal shelf (the Central Iberian Zone); (iii) a graben
that trapped a great thickness of sediments (the
Western Asturian–Leonese Zone; Perez Estaun et al.,
1990); and (iv) an external shelf (the Cantabrian Zone;
Truyols et al., 1990).
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198184
The southern Iberia transect shows southward
orogenic vergence and crosses two main tectonic
boundaries coincident with the southern and northern
contacts of the Ossa–Morena Zone (Fig. 1B and C2).
The southern boundary separates the Ossa–Morena
and the South Portuguese zones, being marked by
dismembered oceanic units: several small ophiolitic
klippes, a strip of oceanic amphibolites, and a unit of
schists with some oceanic metabasalts (Bard, 1977;
Eden and Andrews, 1990; Fonseca and Ribeiro, 1993;
Quesada et al., 1994; Castro et al., 1996; Fonseca et
al., 1999). All those units attest the closure of some
oceanic domain. The kinematics of the subsequent
collision was markedly oblique (left-lateral trans-
pression; Crespo Blanc and Orozco, 1988; Silva et
al., 1990). The interpretation of the northern border of
the Ossa–Morena Zone has been the object of some
controversy. Structural work has shown that the
boundary Ossa–Morena Zone/Central Iberian Zone
(Fig. 1C2) is the root of a pile of kilometer-scale
Fig. 2. (A–D) Sketches showing the evolution proposed for the Iberian Mas
perhaps particularly oversimplified. (E) 3D sketch of the Iberian Massif
structure of this orogenic region (after Simancas et al., 2002). SPZ: South
Zone; GTMZ: Galicia Tras-os-Montes Zone; ALZ: Western Asturian–Leo
southward-vergent recumbent folds and thrusts (Vau-
chez, 1975; Exposito et al., 2002; Simancas et al.,
2003). Furthermore, the boundary unit is made up of
metasediments, eclogites, gneisses, and amphibolites
with oceanic affinity (Abalos et al., 1991; Azor et al.,
1994; Ordonez Casado, 1998; Gomez-Pugnaire et al.,
2003; Lopez Sanchez-Vizcaıno et al., 2003). Thus,
despite some controversy based on the still poorly
determined age of the high-pressure metamorphic
event (Schafer et al., 1991; Ordonez Casado, 1998),
this boundary can be considered as another orogenic
suture (Burg et al., 1981; Matte, 1986; Azor et al.,
1994; Simancas et al., 2001). In this respect, there are
noticeable differences in the Ordovician to Devonian
stratigraphy of the Ossa–Morena and Central Iberian
zones (Robardet and Gutierrez Marco, 1990),
although faunal affinities suggest that the continental
blocks of the Central Iberian and Ossa–Morena zones
would not have got substantially separated (Robardet,
2002, 2003). Consequently, both boundaries of the
sif during the Variscan orogeny. The evolution of the GTMZ zone is
in Late Carboniferous time, which emphasizes the non-cylindrical
Portuguese Zone; OMZ: Ossa–Morena Zone; CIZ: Central Iberian
nese Zone; CZ: Cantabrian Zone.
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198 185
Ossa–Morena Zone seem to correspond to orogenic
sutures, although the southern one (South Portuguese
Zone/Ossa–Morena Zone) may be the suture of the
Rheic Ocean, while the northern one may witness the
welding of a terrane (the Ossa–Morena Zone) closely
tied to the Gondwana margin (Central Iberian Zone).
Closing of oceanic domains in southwest Iberia was
completed in Devonian time because the early colli-
sional deformation in the Ossa–Morena Zone is of
Devonian age. Nevertheless, an extensional and
magmatic event recognized in a large area of south-
west Iberia took over during the latest Devonian–
earliest Carboniferous, interrupting the normal devel-
opment of the collision (Simancas et al., 2003).
Before the Variscan orogenic events (i.e., in Early
Palaeozoic times), the Ossa–Morena Zone underwent
a rifting that started in Middle Cambrian, breaking a
Lower Cambrian carbonate shelf (Linan and Quesada,
1990). This rifting was highly magmatic, ending with
the creation of the oceanic domains attested by the
sutures referred to above at both boundaries of the
Ossa–Morena Zone.
The correspondence between the sutures cropping
out in southern Iberia and the one(s) indicated by the
allochtonous terranes of northern Iberia is not
straightforward (see different proposals in Bard et
al., 1980; Burg et al., 1981; Matte, 1991, 2002;
Ribeiro et al., 1995; Martınez Catalan et al., 1997,
2002, 2004; Simancas et al., 2002). Independently of
the proposal to be chosen, the opposite orogenic
vergence between the northern and southern Iberia
sections (Fig. 1) suggests opposite subduction polar-
ities. On this view, the Porto–Tomar fault (Ribeiro et
al., 1980) could be a collisional fault derived from a
former transform fault, which connected the opposite
subduction zones as shown in Fig. 2 (Simancas et al.,
2002).
3. The Variscides in Morocco
As in the case of Iberia, a large part of the
Moroccan territory shows the effects of the Variscan
orogeny (Pique and Michard, 1989; Pique, 1994).
Most of that territory corresponds to the Moroccan
Meseta, but Palaeozoic outcrops inside the Alpine
ranges, both in Morocco (Rif, Middle, and High
Atlas) and in northernmost Algeria (Kabilies), also
provide some information about the Variscan events.
However, the Palaeozoic rocks inside the Rif and
Kabilies, as well as those in the Betics, are allochth-
onous (e.g., Sanz de Galdeano et al., 2001).
To the south, the northern African Precambrian
craton constitutes the foreland of the Palaeozoic
Moroccan Variscides (Fig. 3A and B). An intermedi-
ate region, the Anti Atlas, shows a basement
reactivated at the end of the Proterozoic and weakly
affected later by the Late Palaeozoic deformation.
Leaving aside the Anti Atlas, the Variscan regions of
Morocco are usually divided into Western and Eastern
Meseta, separated by the Mesozoic rocks of the
Middle Atlas (Pique et al., 1993). In the Western
Meseta, the following tectonic units can be distin-
guished, from west to east (Fig. 3B): the Coastal
Block, the Central Massif/Rehamna/Jbilete, and the
Nappe zone. The Nappe zone comprises the eastern
borders of the Central Massif, Jbilete, and Ait Tamlil
area, and constitutes the transition to the Eastern
Meseta. The latter shows isolated Palaeozoic outcrops
extending from Midelt to Oujda. Finally, the Sehoul
Block (Pique, 1979; El Hassani, 1991) is a Caledonian
domain with a much reduced extent of outcrop, thrust
onto the Western Meseta (Fig. 3A).
The Central Massif exhibits a complete Palaeozoic
sequence. Lower Palaeozoic sediments formed part of
an extensive platform connected with the Anti Atlas.
Upper Devonian–Lower Carboniferous sediments and
volcanics witness the breaking of that platform and
the development of two NE–SW basins (Tahiri, 1991;
Pique, 1994). To the west, the Coastal Block shares
with the Central Massif a similar stratigraphy except
for the fact that it records the development of a graben
in Middle Cambrian times, as indicated by the
volcanism (Destombes and Jeannette, 1966; Ouali et
al., 2003) and the greater thickness of sediments of
this age (Bernardin et al., 1988; Pique et al., 1995).
The Coastal Block is weakly deformed, so that
tectonic foliation appears only close to a dextral shear
zone, which is the boundary with the Central Massif
(Fig. 3B; Pique et al., 1980). Tectonic foliation of
Westphalian–Stephanian age has general development
in the Central Massif (El Hassani, 1991; Tahiri, 1994),
where a few granitic plutons intrude the Palaeozoic
sequence. The eastern Central Massif (Nappe zone)
presents a distinctive Devonian succession (calcareous
flysch, olistoliths; Zahraoui, 1994), as well as a
Fig. 3. (A) Location of the Moroccan Variscides in the Alleghanian–Variscan Orogenic belt. (B) Variscan zones of Morocco (compiled after
different maps in Pique, 1994). (C) Inferred cross-section of the Moroccan Variscides at Late Visean to Namurian time (modified after Pique,
1994).
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198186
particular style and age of deformation (Bouabdelli,
1994), which makes it transitional to the Eastern
Meseta.
The Eastern Meseta (Fig. 3B) can be distin-
guished from the Western Meseta in two main
respects. First, it records different sedimentary
environments, the Silurian being represented in the
Eastern Meseta by pelagic deposits and the early–
middle Devonian by turbidites (Hoepffener, 1987;
Zahraoui, 1994). Second, both the intensity (greater
in the Eastern Meseta) and the age of the first
deformational event (Late Devonian in the Eastern
Meseta and Carboniferous in the Western Meseta)
are different (Hoepffener, 1987, 1994). As a whole,
the Eastern Meseta can be interpreted as recording
some crustal thinning, which gave way to an open
sea to pelagic sedimentary realm during the upper
part of the Early Palaeozoic. Later on, during the
early–middle Devonian, it became a trough of
turbiditic sediments, which announced a Late Devon-
ian deformation (Pique , 1994). Interestingly,
although no Devonian rocks outcrop to the east of
the Eastern Meseta, there are some indications
(Devonian blocks in Carboniferous deposits) which
can be taken to suggest that a carbonate platform
would have existed east of the turbiditic trough
(Hoepffener, 1987). In the allochthonous Palaeozoic
rocks of the Malaguide Complex (Betic orogen,
southeast Iberia; Fig. 1B), Herbig (1985) and Herbig
and Stattegger (1989) have described just the same
large blocks of Devonian limestones inside Visean
deposits, so that the Malaguide and the Eastern
Meseta might be palaeogeographically equivalent,
perhaps representing the same trough bordered by
the same carbonate platform.
The Late Devonian and Early Carboniferous
evolution seems broadly common in the Moroccan
Variscides. This time span is represented by clastic
sedimentation and interbedded volcanic rocks, sug-
gesting some kind of extensional tectonics. Firstly,
sedimentation concentrated in two main grabens, the
Sidi-Bettache and the Azrou–Kenifra basins, but
from the middle Visean on, it expanded to a larger
area (Pique, 1994). In the Western Meseta, the Late
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198 187
Devonian and Early Carboniferous volcanic rocks
are tholeiitic to alkaline basalts, which characterize
extensional tectonic settings. However, the volcanism
of the same age in the Eastern Meseta is calc-
alkaline and dominated by andesites (Karbouch,
1994).
In the Eastern Meseta (Fig. 3B), Lower Carbon-
iferous sediments lie unconformable over Lower
Palaeozoic deposits previously deformed and meta-
morphosed, thus indicating that the age of the first
deformational event is Late Devonian. This first
deformation was earlier here than in the Western
Meseta, where Lower Carboniferous rocks conform-
ably overlie Devonian ones and deformation did not
start until the Visean or later. Apparently, the thinned
crust extending at least from Marrakech to Oujda (the
Eastern Meseta) had low strength by the time when
the first compressive Variscan stresses were arising, so
that deformation started earlier and thus concentrated
here (Fig. 3C).
Based on the early age of the deformation, the
synmetamorphic character, and the western vergence,
the Eastern Meseta is thought to be the internal zone
of the Moroccan Variscides (Boulin et al., 1988; Pique
and Michard, 1989; Pique et al., 1993; Hoepffener,
1994). Accordingly, the tectonic arrangement of the
outcropping Moroccan Variscides would be, from NW
to SE: an external zone (the Coastal Block and Central
Massif), an internal zone (the Eastern Meseta),
another external zone (mostly hidden by a cover, but
partially represented in the Anti Atlas region), and the
African cratonic foreland. Since neither ophiolites nor
eclogites crop out anywhere, most authors consider
the Moroccan Variscides as an intracontinental orogen
(Fig. 3C; Pique and Michard, 1989; Pique et al., 1993;
Hoepffener, 1994). Nevertheless, the above statement
is misleading in the sense that the Moroccan transect
must fit into the Late Palaeozoic plate tectonic
scenario, which includes the closing of at least one
oceanic realm, the Rheic Ocean. On this view, it has
been suggested that a main orogenic suture could be
hidden under the cover, somewhere to the southeast of
the Eastern Meseta (Boulin et al., 1988), but this
interpretation is not, however, without problems (see
discussion in Pique et al., 1993; Pique, 1994).
Actually, the Moroccan Variscides must represent an
incomplete transect of the orogen, which lacks the
main suture zone.
4. Building up the Variscan tectonic frame
The Variscan tectonic frame depicted in Fig. 4
arises out of the following proposals of linkage
between the different outcropping domains.
4.1. Links between Iberia and Central Europe
The main tectonic contacts between crustal domains
in central and southern European Variscides are well
known, the broad picture being dominated by an
arcuated geometry, namely the Ibero–Armorican arc
(see reviews in Bard et al., 1980;Matte and Burg, 1981;
Behr et al., 1984; Matte, 1986, 1991; Franke, 1989,
2000; Ribeiro et al., 1995; Crowley et al., 2000b;
Simancas et al., 2002; Winchester et al., 2002).
Palaeontological and palaeomagnetic data help us to
constrain how far away the continental masses were
from each other at different times in the Palaeozoic
(Torsvik et al., 1990; Robardet et al., 1993; Tait et al.,
1997; Nys&ther et al., 2002; McKerrow et al., 2000;
Robardet, 2003). Therefore, a number of tectonic
contacts considered as sutures due to their relationship
with ophiolites and high-pressure metamorphic rocks
seem to record the amalgamation of continental blocks
that were drifted apart from the Gondwana margin, but
never reached a sufficient degree of separation enough
so as to provoke faunal dissimilarities (Matte, 2001;
Nys&ther et al., 2002; Kemnitz et al., 2002). The
terranes bounded by such second-order sutures are
collectively named Armorican Terrane Assemblage.
The largest of those terranes was perhaps made up of
the Saxothuringian Zone (central Europe) and the
Ossa–Morena Zone (Iberia), which share many geo-
logical features and are bounded by similar suture
contacts (Matte, 1991) that we correlate. The alter-
native model considering that the suture of the French
Massif Central was continuous with both the Galicia-
Tras-Os-Montes (NW Iberia) and the Ossa–Morena/
Central Iberian sutures (Matte and Burg, 1981; Matte,
1986) has been criticized by Robardet (2002) because
such suture would cut across two regions (Armorica
and Central Iberian Zone) with strong faunal and
stratigraphic similarities in the Ordovician. On this
ground, we propose that a transfer fault would interrupt
the continuity of the Massif Central oceanic domain,
thus providing palaeogeographic continuity (Fig. 5;
Simancas et al., 2002).
Fig. 4. Tectonic frame of the Variscan (Acadian–Alleghanian) Orogenic belt at the end of the Palaeozoic. The prominent features shown in this
picture are: the extent of the Avalonian Composite Terrane (ruled area); the Variscan main suture (RHS, LS, SPS, and CA) and secondary
sutures (S2, S3); the rifted areas in the margin of Gondwana (dashed bands); the regional vergences (arrows), the collisional faults (thick
continuous lines), and the deformation fronts (thick dashed lines). The picture has been composed by drawing on our own data as well as on the
following sources of information: Hatcher (1987) (southern Appalachians); Keppie (1982) (northern Appalachians and Newfoundland); Lefort
and Ben Salmia (1992) (Nova Scotia–Newfoundland); Pique et al. (1993) and Houari and Hoepffener (2003) (Morocco); Matte (1986,1991)
(Europe). The fitting of continents at the end of the Palaeozoic is after Le Pichon et al. (1977).
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198188
The Rheic Ocean between Avalonia and the
Armorican Terrane Assemblage seems to be repre-
sented by the suture between the Rhenohercynian and
Saxothuringian zones of central Europe (Behr et al.,
1984; Franke, 1989, 2000), which can be correlated
with the suture represented by the Lizard ophiolite in
SW England (Behr et al., 1984; Matte, 1986, 1991)
and the boundary South Portuguese Zone/Ossa–
Morena Zone in SW Iberia (Crespo Blanc and Orozco,
1988; Fonseca and Ribeiro, 1993). Moreover, there are
Fig. 5. (A) Sketch of the putative palaeogeography before consumption of the Rheic Ocean and amalgamation of the peri-Gondwana terranes to
the Gondwana margin. The approximate sites from where future ophiolites will derive are indicated by stars. Note, however, that those
ophiolites apparently related to the Rheic Ocean may have come from small marginal basins rather than being chips of the floor of the Rheic
Ocean. The sketch may be particularly oversimplified for the Galicia Tras-os-Montes ophiolite. CIZ: Central Iberian Zone; CZ: Cantabrian
Zone; EMM: Eastern Moroccan Meseta; KA: Kabilies; MG: Malaguide–Gomaride complex; MN: Montagne Noire; MZ: Moldanubian Zone;
NCA: North-Central Armorica; OMZ: Ossa–Morena Zone; RHZ: Rhenohercynian Zone; SPZ: South Portuguese Zone; STZ: Saxothuringian
Zone; ALZ: Western Asturian–Leonese Zone; WMR: Western Moroccan Rift. (B) Sketch of the orogenic belt resulting from collision of the
continental pieces shown in (A); stars indicate ophiolite outcrops.
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198 189
robust points of similarity between the sedimentary
sequences in southwest England, the Rhenohercynian
Zone in Germany, and the South Portuguese Zone in
SW Iberia (Oliveira et al., 1979; Franke and Engel,
1982; Holder and Leveridge, 1986). North of the
Rhenohercynian Zone, the Caledonian foreland (i.e.,
the Avalonian regions not reworked by the Late
Palaeozoic continental collision) crops out. At south-
ern central Europe, the Pyrenean–Alpine–Carpathian–
Dinaride deformation belt has obliterated the southern
part of the Variscan orogen, reworking some internal
areas (Neubauer and Handler, 2000) and most of its
southern external zone. Nevertheless, a number of
points of convergence between the Palaeozoic out-
crops of the Western Asturian–Leonese Zone in NW
Iberia, the Pyrenees, and the Montagne Noire in SE
France have been recognized for some time (Matte,
1991; Demange, 1994). Likewise, the present-day
dispersed Palaeozoic outcrops in southern Sardinia,
Minorca, and the Catalonian Coastal Ranges of NE
Iberia were part of this external zone.
4.2. Links between Iberia and northern Africa
The Anti Atlas and the Meseta in Morocco as
well as the Iberian Massif and a number of outcrops
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198190
in Central Europe show calc-alkaline plutonic and
volcanic igneous rocks of latest Neoproterozoic age
overlain by Lower Cambrian carbonates (Pique,
1981; Sanchez Carretero et al., 1990; Neubauer,
2002). These plutons and volcanosedimentary for-
mations are manifestations of an extended postoro-
genic magmatism of the Pan-African orogeny, the
Lower Cambrian being transgressive over the ruins
of that Late Precambrian orogen. Since the Middle
Cambrian, a number of rifted areas started to be
defined, thus giving way to different Variscan
domains. The main Variscan domains in Iberia and
northern Africa are briefly described in the following
paragraphs.
The Western Asturian–Leonese Zone in NW Iberia
was a graben that accumulated about 10,000 m of
Cambrian and Ordovician deposits, although syn-
sedimentary volcanic rocks are scarce (Perez Estaun et
al., 1990). Less thick (about 5000 m), though never-
theless remarkable, Lower Palaeozoic successions
have been described by Demange (1994) in the
Montagne Noire and the Pyrenees.
The Ossa–Morena Zone of southern Iberia was a
Cambro-Ordovician rifted area that shows copious
magmatism and evolved to form two oceanic realms:
one at the contact with the present-day South
Portuguese Zone, the Rheic Ocean (Bard, 1977;
Fonseca and Ribeiro, 1993), probably created in the
Ordovician; the other at the contact with the Central
Iberian Zone, perhaps a strait oceanic corridor which
turned the Ossa–Morena into a Silurian terrane hardly
independent from Gondwana (Matte, 1986; Simancas
et al., 2001; Gomez-Pugnaire et al., 2003).
The Moroccan Western Meseta records a volcanic
graben starting in Middle Cambrian, but it aborted
soon, in Late Cambrian. The crustal thinning of the
Eastern Moroccan Meseta apparently started later, in
Ordovician times, but persisted until Middle Devon-
ian times (Hoepffener, 1987; Pique, 1994).
To conclude, the Moroccan Meseta and the Central
Iberian, Western Asturian–Leonese, and Cantabrian
zones of Iberia would have belonged to a common
pre-orogenic domain at the border of Gondwana: a
continental crust with some thinned strips recorded as
sedimentary troughs. The affinity between these
regions and the Brittany–Montagne Noire–Barrandian
regions of central Europe is reinforced by strong
similarities of Palaeozoic faunas (see reviews in
Pique, 1994; Robardet, 2003). Upon closer inspection,
a number of strong similarities can be observed
between the Eastern Moroccan Meseta, the Mala-
guide/Gomaride complex outcropping inside the
Betic/Rif Alpine Ranges, the Western Asturian–
Leonese Zone in NW Iberia, the Pyrenees, and the
Montagne Noire in SE France. All these areas
recorded Early Palaeozoic sedimentation in troughs
probably related to thinned crustal areas, with scarce
syn-extensional volcanism. Accordingly, all these
regions were probably in approximate palaeogeo-
graphic continuity. On the contrary, there are no
equivalents in Morocco of the highly magmatic
Cambro-Ordovician rift (ending with creation of
oceanic crust), represented by the Ossa–Morena Zone
in Iberia and the Saxothuringian Zone in central
Europe.
Upper Devonian and Lower Carboniferous depos-
its are mostly terrigenous and volcanosedimentary in
Morocco and southwest Iberia. They are interpreted as
revealing an extensional tectonic environment at this
time, later on switched to a generalized compression.
The reasons for the extension in question are
debatable: in Morocco, it has been envisaged as a
pull-apart basin formation in a broader context of
transpression (Pique, 1994); in southwest Iberia, the
magmatic and extensional manifestations have been
related to a mantle plume (Simancas et al., 2003).
Independently of the interpretation preferred, the
geographic distribution of the regions recording this
extension has little to do with the Early Palaeozoic
palaeogeographic domains.
A last issue to be emphasized is the comparison of
the Variscan Late Carboniferous to Permian granitoids
of Morocco and Iberia, which provide additional
support to the broad correlation proposed above. In
this respect, the granites of the Moroccan Central
Massif (Fig. 3; Mahmood and Bennani, 1984;
Amenzou and Mouraouah, 1995) show petrographic
and geochemical features enabling us to consider
them equivalent to others in the Central Iberian Zone
(Fig. 1; Bea, 2004). In the same way, the calc-alkaline
high-K granitoids outcropping in the Eastern Meseta
(El Hadi et al., 2003) are similar to the granitoid
stocks described in the Cantabrian Zone (Gallastegui
et al., 2004). To the northeast, a similar plutonic
zonation is found in the Moldanubian/Alps region
(Finger and Steyrer, 1990).
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198 191
4.3. Links between northwest Africa and eastern
North America
As in the case of the Anti Atlas and the Moroccan
Meseta, in the eastern Appalachians, there are some
areas (the Avalon Peninsula, the Boston area, and the
eastern Piedmont) which recorded igneous and
metamorphic events of around 600 Ma. However,
those areas are here exotic when compared to most of
the North America margin and, accordingly, were
African (Gondwanan) at that time (Rodgers, 1982;
Suppe, 1985). They were later on accreted to
America, after the closure of the Iapetus Ocean
(Taconic plus Acadian orogenies). A witness of this
Early Palaeozoic ocean is the discontinuous but
distinct ophiolite line mapped along most of the
Appalachians and northern Newfoundland. However,
this ophiolitic line apparently marks oceanic domains
developed between volcanic arcs or other terranes and
the North America margin, to which they were
accreted (Taconic orogeny) before the complete
(Acadian) docking of Avalonia in Devonian time
(Rodgers, 1982; Keppie, 1982; Suppe, 1985). For
instance, the outcrops of mafic–ultramafic complexes
in the southern Appalachians are interpreted as
remains of a small oceanic domain between a
Piedmont Terrane and the continental margin, while
a more cryptic suture of the Iapetus Ocean (i.e., the
northern edge of the Avalonian terrane) is envisaged
to be found to the southeast, in central Piedmont
(Hatcher, 1987).
Regardless of the location of sutures related to the
Iapetus closure, we are here concerned with the
southern edge of the Avalonian terrane (i.e., the suture
marking the Devonian to Carboniferous closing of the
Rheic Ocean separating Avalonia and Gondwana). In
the southern Appalachians, the Rheic suture is
probably hidden under the Coastal Plain. In the
northern Appalachians, the location of this suture is
not without controversy, with the main discussion
being focused on the relationships between Avalonia
and the Meguma terrane, which crops out just to the
southeast, in southern Nova Scotia. Based on the
finding of similar detrital zircon age populations,
Murphy et al. (2004) have considered that Avalonia
and Meguma were not two separate terranes, but a
single one accreted to Laurentia–Baltica. This
assumption would imply the location of the Rheic
suture (between Avalonia and Gondwana) somewhere
to the southeast of Nova Scotia, blurred by the
Mesozoic opening of the Atlantic Ocean. However,
the hypothesis considering that Avalonia and Meguma
accreted as separate terranes (Schenk, 1997) seems to
us more plausible based on: i) the Devonian defor-
mation of Meguma, which is more easily explained as
due to its collision with Avalonia; and ii) the
prominent linear magnetic anomaly extending from
Nova Scotia to southern Newfoundland (the Collector
Anomaly), which strongly suggests the location of a
suture here (Lefort and Ben Salmia, 1992; Lefort et
al., 1996). Thus, in our view, the Collector Anomaly
marks the boundary between the Avalon and Meguma
terranes, representing the scar of the Rheic Ocean.
Furthermore, according to Lefort and Ben Salmia
(1992) and Lefort et al. (1996), the Moroccan Meseta
and southern Nova Scotia would belong to the same
crustal domain in Early Palaeozoic times, based on
their similar geophysical features.
The Ordovician to Devonian deformation resulting
from the complex docking of Avalonia to the North
American continent is neither found in the Moroccan
Meseta nor in Iberia. Only the allochthonous Sehoul
block in northern Morocco exhibits an equivalent
Caledonian imprint (El Hassani, 1991) and, accord-
ingly, we suggest that this block is a portion of
Avalonia. The two arguments mentioned above (i.e.,
the Collector Anomaly as the main suture of the Late
Palaeozoic orogeny and the Sehoul block as a part of
Avalonia) are essential to our tectonic picture envis-
aged below.
5. The tectonic frame of the Variscan–Alleghanian
orogen
Arthaud and Matte (1977) were the first to present
an integrated kinematic picture (a megadextral shear
zone) for the Late Palaeozoic orogenic belt extending
throughout Europe, northwest Africa, and eastern
North America. As advanced above, a finer-grained
analysis of the tectonic links between the outcropping
portions of this orogen in Europe has already been
furnished by a number of authors. However, there are
few models on the connections between Iberia, Africa,
and America. Most of the models in question suggest
the linkage of the southwest Iberia zones (Ossa–
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198192
Morena and South Portuguese zones) with the
Moroccan Meseta, either in a simple way (Pique,
1981; Hoepffener, 1987) or placing in-between
dextral transcurrent faults (Chalouan and Michard,
1990; Houari and Hoepffener, 2003). However, the
Middle Cambrian to Early Carboniferous stratigraphy
of southwest Iberia reveals a history without counter-
part in Morocco.
Our interpretation of the overall tectonic frame is
shown in Fig. 4. The northwest boundary of Avalonia
has been delineated as passing through the central
Piedmont suture (Hatcher, 1987), the central New
England (Suppe, 1985), north of the Avalon Peninsula
(Keppie, 1982), and the Solway line in the British
Caledonides (Berthelsen, 1992). The outline of south-
ern Avalonia, marked by the scar of the Rheic Ocean,
looks more crooked: from west to east, it follows the
Collector Anomaly, the Sehoul block, and the internal
boundaries of the South Portuguese and Rhenohercy-
nian zones. If we accept the validity of these northern
and southern boundaries for the Avalonian terrane, it
then becomes apparent that this terrane was markedly
wider to the east than to the west (Fig. 4), with a
maximum width in the Newfoundland Grand Banks.
The Sehoul block in northern Morocco (Figs. 3 and
4) is interpreted as a border of the Avalonian Grand
Banks salient, thrust to the south onto Gondwana.
Like the majority of the Appalachians, the Sehoul
block records a Caledonian deformation, but this
deformation did not affect other regions like the
Moroccan Meseta and most of the European Varis-
cides. Nevertheless, a Caledonian deformation has
been found in some outcrops of the Rhenohercynian
Zone (Franke, 2000), and it may also exist in the
covered Lower Palaeozoic rocks of the South Portu-
guese Zone. In NW Iberia, a Caledonian tectonome-
tamorphic event is recorded in some Upper Units of
the Galicia Allochthonous Complex (Abati et al.,
1999; Fernandez-Suarez et al., 2002). Thus, the crust
of the Sehoul block, the South Portuguese Zone, some
Upper Units of the Galicia Allochthonous, and the
Rhenohercynian Zone would be argued to belong to
the southern border of Avalonia (Fig. 4).
The oblique dextral collision between Avalonia
and Gondwana (with the outboard terrane of the
Ossa–Morena–Saxothuringian zones sandwiched in
between) developed a remarkable set of dextral
transcurrent faults in Morocco and eastern North
America. Most of the faults shown in Fig. 4 are
mapped geological structures (Keppie, 1982; Houari
and Hoepffener, 2003) or faults inferred from the
displacement of the Collector Anomaly between Nova
Scotia and Newfoundland (Lefort and Ben Salmia,
1992). South of Newfoundland, we envisage the
suture represented by that magnetic anomaly to be
displaced again towards the north of Morocco (Fig.
4). Here, the suture could be found perhaps under the
Alpine allochthonous units of the Rif, but most
probably has been disrupted, displaced, and subducted
to a considerable extent during the Jurassic to present-
day displacements between Africa and Iberia (e.g.,
Ricou, 1994). Nevertheless, a survivor witness of the
suture in this area may be some rocks recently
dredged about 100 km south of the southwest Iberian
coast, which are similar to those cropping out in the
northern South Portuguese Zone and its boundary
with the Ossa–Morena Zone (Vegas et al., 2004).
Furthermore, a dextral displacement of the suture in
that missing area between Iberia and Africa can be
inferred from the evidence of a deep-crustal Late
Palaeozoic shear zone in the Kabilies (Fig. 4;
Bossiere, 1980; Bouillin et al., 1984; Pique et al.,
1993). This shear zone is described as approximately
east–west, dextral, and cross-cutting low grade meta-
morphic rocks, with the shear zone itself exhibiting a
medium-pressure, high-grade metamorphism. A gran-
ite dated as 271 (Rb–Sr)/273 (U–Pb) Ma (Bossiere
and Peucat, 1986; Peucat and Bossiere, 1991)
intruded after the blastomylonitization in this shear
zone.
The prominent spur of Avalonia, which approx-
imately coincides with the present-day Grand Banks,
played a major role in the complex pattern of the
central part of the Variscan orogenic belt. This is why
the main Variscan suture presents an abrupt change of
orientation, cropping out again in southern Iberia, as
the boundary between the South Portuguese and
Ossa–Morena zones (Fig. 4). The prolongation of
this main suture in southern England (Lizard ophio-
lite) and along the boundary between the Rhenoher-
cynian and Saxothuringian zones is generally
accepted (e.g., Matte, 2002). From a kinematic point
of view, our reconstruction suggests that the Grand
Banks’ indentor would have originated the Carbon-
iferous prominent sinistral shearing in southern Iberia,
in addition to some counterclockwise rotation of this
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198 193
region. Thus, the Grand Banks’ indentor may have
been more influential on the configuration of the
Ibero–Armorican arc than the usually envisaged
active indentor in the core of the arc (Matte and
Ribeiro, 1975; Burg et al., 1981; Matte, 1986, 1991).
In this respect, we note that recent palaeomagnetic
studies by Weil et al. (2001) in the Asturian core of
the Ibero–Armorican arc suggest that most of the
tightening of this megastructure would have taken
place in latest Carboniferous–Permian time, substan-
tially later than the timing required by models based
on strong indentation in the core of the arc. Our
reconstruction furnishes us with a kinematic picture
somewhat more compatible with those palaeomag-
netic results because most of the rotations in the
Asturian core of the arc can be delayed until a late
collisional stage.
Despite the above statement, the Grand Banks’
indentor did not behave as rigidly as, say, the Indian
indentor in the Himalayan collision (Tapponier et al.,
1982); on the contrary, it underwent an important
deformation reshaping it. In this respect, some
indentation of the Iberian core, on the one hand, and
of northwest Africa, on the other hand, can be inferred
from the fault pattern: escape tectonics in Iberia is
illustrated in Figs. 2B and 4, while some northward
penetration of Africa is suggested by the Nova Scotia–
Newfoundland escape fault arrangement (Fig. 4).
Actually, the Alleghanian deformation in the northern
Appalachians is dominated by strike–slip faults
(Keppie, 1982; Rodgers, 1982).
Second-order sutures between peri-Gondwana ter-
ranes and the border of Gondwana cannot be followed
all along the orogen. The suture located at the
boundary between the Saxothuringian and the Mol-
danubian zones in central Europe seems to be
equivalent to the boundary Ossa–Morena Zone/
Central Iberia Zone (S2 in Fig. 4; see also Fig. 5A).
There are no data on the possible continuation to the
southwest of this suture, but the gneissic rocks found
in drill holes on the Atlantic platform of Morocco
(Kreuzer et al., 1984) could be related to its
continuation. On the other hand, the Massif Central
suture in France (S3 in Fig. 4) apparently does not
prolong towards Iberia (as discussed above), abutting
perhaps on a transfer fault (Fig. 5).
The schematic palaeogeographic picture proposed
here for the oceanic domains before continental
collision took place is sketched in Fig. 5A. In this
figure, the approximate sites from where future
ophiolites will derive are suggested by stars, although
the ophiolites apparently related to the closure of the
Rheic Ocean may represent, rather than the ocean
itself, pull-apart basins (the Lizard complex in Corn-
wall; Cook et al., 2002), young small boceansQ (theRhenohercynian ocean; Franke, 2000), back-arc
basins (the Beja–Acebuches ophiolite in southwest
Iberia; Quesada et al., 1994), or other particular
domains of a much more complex palaeogeographic
scenario. As for the Galicia Tras-os-Montes ophiolitic
units (Arenas et al., 2004), they may constitute a
complex ophiolite, including units coming from
different oceanic domains.
The continental grabens that developed in Early
Palaeozoic times on the margin of Gondwana are also
very schematically depicted in Fig. 5A: these are the
Middle Cambrian Western Moroccan Rift, in the
Coastal Block, and a long strip of more or less aligned
grabens of Ordovician–Early Devonian age, now
represented by the Eastern Meseta and the Palaeozoic
of Kabilies/Malaguide/Gomarides (inliers in Alpine
Ranges), plus the Cambro-Ordovician rifted area of
the Western Asturian–Leonese Zone and the Mon-
tagne Noire–Pyrenees. This strip of grabens is the
southernmost domain influenced by the Early Palae-
ozoic extension on the northern border of Gondwana.
6. Conclusion
We have proposed here a tectonic frame—obvi-
ously simplified, but coherent—for the Variscan–
Alleghanian orogenic belt from central Europe to the
southern Appalachians at both pre-collisional and
late-collisional stages. Apart from other geological
and geophysical data available from previous works,
the two keystones in our reconstruction are as follows:
(i) the suture-bounded Variscan zones of Iberia (Ossa–
Morena and South Portuguese zones in the southern
transect, and the allochthonous Galicia Tras-os-Mon-
tes Zone in the northern transect) have no equivalent
in the Moroccan Variscides; and (ii) the Moroccan
Meseta shows stratigraphic similarities with the
central and northern zones of Iberia, considered to
have been part of the Gondwana rifted margin at early
Palaeozoic times. Thus, the northern Iberia palae-
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198194
ogeographic zones would prolong in the Moroccan
Meseta through an eastward arcuate structure.
Accordingly, the main suture of the Variscan orogen
(Rheic Ocean), which is represented at the boundary
between the South Portuguese and Ossa–Morena
zones, moulds around an Avalonian spur (Grand
Banks indentor), being laterally translated to south-
eastern Nova Scotia–Newfoundland. The Caledonian
Sehoul block in northern Morocco is considered to be
part of that Avalonian spur, as well as the crust of the
South Portuguese Zone in SW Iberia. We consider this
Avalonian (Grand Banks) indentation and the counter-
parts late-collisional indentations of Iberia and north-
west Africa to have played an important role on the
tectonic pattern of the central segment of the Variscan
orogenic belt.
Acknowledgements
Financial support has been given by the AECI
(Agencia Espanola de Cooperacion Internacional)
grants number 65/03/P and 65/04/R/E, the Junta de
Andalucıa grant number A11/02 (M), and the Minis-
terio de Ciencia y Tecnologıa grant number BTE2003-
05128. We thank Francisco Gonzalvez Garcıa for
improving our English text. Comments and sugges-
tions by two anonymous reviewers are greatly
acknowledged.
References
Abalos, B., Gil Ibarguchi, J.I., Eguiluz, L., 1991. Cadomian
subduction/collision and Variscan transpression in the Bada-
joz–Cordoba shear belt, southwest Spain. Tectonophysics 199,
51–72.
Abati, J., Dunning, G.R., Arenas, R., Dıaz Garcıa, F., Gonzalez
Cuadra, P., Martınez Catalan, J.R., Andonaegui, P., 1999. Early
Ordovician orogenic event in Galicia (NW Spain): evidence
from U–Pb ages in the uppermost unit of the Ordenes Complex.
Earth and Planetary Science Letters 165, 213–228.
Amenzou, M., Mouraouah, A. El Arab, 1995. Classification
genetique des granitoRdes hercyniens du Massif Central mar-
ocain (Zaer, Oulmes, Ment; Meseta nord-occidentale, Maroc),
d’apres la typologie du zircon. Comptes Rendus de l’Academie
des Sciences Paris 320 (IIa), 469–476.
Arenas, R., Gil Ibarguchi, J.I., Gonzalez Lodeiro, F., Klein, E.,
Martınez Catalan, J.R., Ortega Girones, E., de Pablo Macia,
J.G., Peinado, M., 1986. Tectonostratigraphic units in the
complexes with mafic and related rocks of the NW of the
Iberian Massif. Hercynica 2, 87–110.
Arenas, R., Dıaz Garcıa, F., Martınez Catalan, J.R., Sanchez
Martınez, S., 2004. Zona de Galicia-Tras-Os-Montes. Unidades
ofiolıticas. In: Vera, J. (Ed.), Geologıa de Espana. SGE-IGME,
Madrid, pp. 150–154.
Arthaud, F., Matte, Ph., 1977. Late Palaeozoic strike–slip faulting in
southern Europe and northern Africa: result of a right-lateral
shear zone between the Appalachians and the Urals. Geological
Society of America Bulletin 88, 1305–1320.
Azor, A., Gonzalez Lodeiro, F., Simancas, J.F., 1994. Tectonic
evolution of the boundary between the Central Iberian and
Ossa–Morena zones (Variscan Belt, southwest Spain). Tectonics
13, 45–61.
Bard, J.P., 1977. Signification tectonique des metatholeites
d’affinite abyssale de la ceinture de basse pression d’Aracena
(Huelva, Espagne). Bulletin de la Societe Geologique de France
19, 385–393.
Bard, J.P., Burg, J.P., Matte, Ph., Ribeiro, A., 1980. La chaine
hercynienne d’Europe occidentale en termes de tectonique des
plaques. 26eme Congres Geologique International, Paris,
Colloque C6. Memoires BRGM 108, pp. 233–246.
Bea, F., 2004. La naturaleza del magmatismo de la Zona
Centroiberica: consideraciones generales y ensayo de correla-
cion. In: Vera, J. (Ed.), Geologıa de Espana. SGE-IGME,
Madrid, pp. 128–133.
Behr, H.J., Engel, W., Franke, W., Giese, P., Weber, K., 1984.
The Variscan belt in Central Europe: main structures, geo-
dynamic implications, open questions. Tectonophysics 109,
15–40.
Bernardin, C., Cornee, J.J., Corsini, M., Mayor, S., Muller, J.,
Tayebi, M., 1988. Variations d’epaisseur du Cambien moyen en
Meseta marocaine occidentale: signification geodynamique des
donnees de surface et de subsurface. Canadian Journal of Earth
Sciences 25, 2104–2117.
Berthelsen, A., 1992. Mobile Europe. In: Blundell, D., Freeman,
R., Mueller, S. (Eds.), A Continent Revealed. The European
geotraverse. Cambridge University Press, Cambridge, UK,
pp. 11–32, 153–164.
Bossiere, G., 1980. Un complexe metamorphique polycyclique et sa
blastomylonitisation. Etude petrologique de la partie occidentale
du massif de Grande Kabylie (Algerie). PhD thesis, University
of Nantes, France.
Bossiere, G., Peucat, J.J., 1986. Structural evidence and Rb–Sr, 39–
40 Ar mica age relationships for the existence of an Hercynian
deep crustal shear zone in Grande Kabilie (Algeria) and its
Alpine reworking. Tectonophysics 121, 277–294.
Bouabdelli, M., 1994. La Tectonique de l’Est du Massif hercynien
central (zone d’Azrou-Khenifra). Geologie du Paleozoique du
Maroc central et de la Meseta orientale, Bulletin de l’Institut
Scientifique (Rabat) Numero Special, vol. 18, pp. 145–168.
Bouillin, J.P., Bossiere, G., Bourrouilh, R., Coutelle, A., Durand-
Delga, M., 1984. Mise au point sur l’age des socles metamor-
phiques kabyles (Algerie). Comptes Rendus de l’Academie des
Sciences Paris, Serie II 298, 655–660.
Boulin, J., Bouabdelli, M., Houicha, E., 1988. Evolution paleo-
geographique et geodynamique de la chaıne paleozoRque du
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198 195
Moyen Maroc: un essai de modelisation. Comptes Rendus de
l’Academie des Sciences Paris 306 (II), 1501–1506.
Burg, J.P., Iglesias, M., Laurent, Ph., Matte, Ph., Ribeiro, A.,
1981. Variscan intracontinental deformation: the Coimbra–
Cordoba Shear zone (SW Iberian Peninsula). Tectonophysics
78, 161–177.
Castro, A., Fernandez, C., de la Rosa, J., Moreno Ventas, I., Rogers,
G., 1996. Significance of MORB-derived amphibolites from the
Aracena metamorphic belt, southwest Spain. Journal of Petrol-
ogy 37, 235–260.
Chalouan, A., Michard, A., 1990. The Ghomarides nappes, Rif
Coastal Range, Morocco: a Variscan chip in the Alpine Belt.
Tectonics 9, 1565–1583.
Cook, C.A., Holdsworth, R.E., Styles, M.T., 2002. The emplace-
ment of peridotites and associated oceanic rocks from the
Lizard Complex, southwest England. Geological Magazine
139, 27–45.
Crespo Blanc, A., Orozco, M., 1988. The Southern Iberia Shear
Zone: a major boundary in the Hercynian folded belt.
Tectonophysics 148, 221–227.
Crowley, Q.G., Floyd, P.A., Winchester, J.A., Franke, W., Holland,
J.G., 2000a. Early Palaeozoic rift-related magmatism in
Variscan Europe: fragmentation of the Armorican Terrane
Assemblage. Terra Nova 12, 171–180.
Crowley, Q.G., Floyd, P.A., Stodra, V., Winchester, J.A.,
Holland, J.G., 2000b. The Marianske–Lazne Complex:
Remnants of a Subducted Early Palaeozoic Seaway. Program
and Abstracts of the 15th International Conference on Basement
Tectonics, Galicia 2000, Variscan–Appalachian Dynamics: The
Building of the Upper Paleozoic Basement, A Coruna (Spain),
pp. 86–89.
Dallmeyer, R.D., Martınez Catalan, J.R., Arenas, R., Gil Ibarguchi,
J.I., Gutierrez Alonso, G., Farias, P., Bastida, F., Aller, J., 1997.
Diachronous Variscan tectonothermal activity in the NW Iberian
Massif: evidence from 40Ar/39Ar dating of regional fabrics.
Tectonophysics 277, 307–337.
Demange, M., 1994. Antevariscan evolution of the Montagne
Noire (France): from a passive margin to a foreland basin.
Comptes Rendus de l’Academie des Sciences Paris 318 (II),
921–933.
Destombes, J., Jeannette, A., 1966. Memoire explicatif de la carte
geotechnique de la Meseta Cotiere a l’Est de Casablanca au 1/
50,000. Notes et Memoires Service geologique Maroc 180.
104 pp.
Eden, C., Andrews, J., 1990. Middle to Upper Devonian
melanges in SW Spain and their relationship to the Meneage
formation in south Cornwall. Proceedings of the Ussher Society
7, 217–222.
El Hadi, H., Tahiri, A., Reddad, A., 2003. Les granitoRdeshercyniens post-collisionnels du Maroc oriental: une province
magmatique calco-alcaline a shoshonitique. Comptes Rendus
Geoscience 335, 959–967.
El Hassani, A., 1991. La Zone de Rabat-Tiflet: bordure nord de la
chaıne caledono-hercynienne du Maroc. Bulletin de l’Institut
Scientifique (Rabat) 15, 1–134.
Exposito, I., Simancas, J.F., Gonzalez Lodeiro, F., Azor, A.,
Martınez Poyatos, D., 2002. La estructura de la mitad septen-
trional de la Zona de Ossa–Morena. Deformacion en el bloque de
muro de un cabalgamiento cortical de evolucion compleja.
Revista de la Sociedad Geologica de Espana 15, 3–14.
Fernandez-Suarez, J., Corfu, F., Arenas, R., Marcos, A., Martınez
Catalan, J.R., Dıaz Garcıa, F., Abati, J., Fernandez, F.J., 2002.
U–Pb evidence for a polyorogenic evolution of the HP–HT units
of the NW Iberian Massif. Contributions to Mineralogy and
Petrology 143, 236–253.
Finger, F., Steyrer, H.P., 1990. I-type granitoids as indicators of a
late Paleozoic convergent ocean–continent margin along the
southern flank of the central European Variscan orogen.
Geology 18, 1207–1210.
Fonseca, P., Ribeiro, A., 1993. Tectonics of the Beja–Acebuches
Ophiolite: a major suture in the Iberian Variscan Foldbelt.
Geologische Rundschau 82, 440–447.
Fonseca, P., Munha, J., Pedro, F., Rosas, J., Moita, P., Araujo, A.,
Leal, N., 1999. Variscan ophiolites and high-pressure meta-
morphism in southern Iberia. Ofioliti 24, 259–268.
Franke, W., 1989. Tectonostratigraphic units in the Variscan belt of
central Europe. Special Paper-Geological Society of America
230, 67–90.
Franke, W., 2000. The mid-European segment of the Variscides:
tectonostratigraphic units, terrane boundaries and plate tectonic
evolution. In: Franke, W., Haak, V., Oncken, O., Tanner, D.
(Eds.), Orogenic Processes: Quantification and Modelling in the
Variscan Belt. Special Publication-Geological Society of Lon-
don, vol. 179, pp. 35–61.
Franke, W., Engel, W., 1982. Variscan sedimentary basins on the
continent and relations with south–west England. Proceedings
of the Ussher Society 5, 259–269.
Gallastegui, G., Suarez, O., Cuesta, A., 2004. Zona Cantabrica.
Magmatismo. In: Vera, J. (Ed.), Geologıa de Espana. SGE-
IGME, Madrid, pp. 47–49.
Gomez-Pugnaire, M.T., Azor, A., Fernandez Soler, J.M., Lopez
Sanchez-Vizcaıno, V., 2003. The amphibolites from the Ossa–
Morena/Central Iberian Variscan suture (Southwestern Iberian
Massif): geochemistry and tectonic interpretation. Lithos 68,
23–42.
Hatcher, R.D., 1987. Tectonics of the southern and central
Appalachian internides. Annual Review of Earth and Planetary
Sciences 15, 337–362.
Herbig, H.G., 1985. An upper Devonian limestone slide block near
Marbella (Betic Cordillera, Southern Spain) and the palaeogeo-
graphic relations between Malaguides and Menorca. Acta
Geologica Hispanica 20, 155–178.
Herbig, H.G., Stattegger, K., 1989. Late Palaeozoic heavy minerals
and clast modes from the Betic Cordillera (southern Spain):
transition from a passive to an active continental margin.
Sedimentary Geology 63, 93–108.
Hoepffener, Ch., 1987. La tectonique hercynienne dans l’Est du
Maroc. PhD thesis Universite Louis Pasteur, Strasbourg, France.
276 pp.
Hoepffener, Ch., 1994. La zone de Midelt–Tazekka–Bsabis, le
domaine interne de la chaine varisque et ses relations avec le
Massif hercynien central. Geologie du Paleozoique du Maroc
central et de la Meseta orientale. Bulletin de l’Institut
Scientifique (Rabat) Numero Special, vol. 18, pp. 169–190.
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198196
Holder, M.T., Leveridge, B.E., 1986. Correlation of the Rhenoher-
cynian Variscides. Journal of the Geological Society (London)
143, 141–147.
Houari, M.R., Hoepffener, Ch., 2003. Late Carboniferous dextral
wrench-dominated transpression along the North African craton
margin (Eastern High-Atlas, Morocco). Journal of African Earth
Sciences 37, 11–24.
Karbouch, F., 1994. Le volcanisme devono-dinantien du Massif
central et de la Meseta orientale. Geologie du Paleozoique du
Maroc central et de la Meseta orientale. Bulletin de l’Institut
Scientifique (Rabat) Numero Special, vol. 18, pp. 191–199.
Kemnitz, H., Romer, R.L., Oncken, O., 2002. Gondwana break-up
and the northern margin of the Saxothuringian belt (Variscides
of Central Europe). International Journal of Earth Sciences
(Geologische Rundschau) 91, 246–259.
Keppie, D., 1982. Terranes in the Northern Appalachians. Maps 1:
5,000,000 and Charts. Nova Scotia Department of Mines and
Energy, Canada.
Kreuzer, H., Muller, P., Reinecke, T., Wissman, G., 1984.
Petrography and K–Ar Dating of the Mazagan Granodiorite
DSDP Leg 79, Holes 544A and 544B. Initial Reports DSDP 79,
Washington (US Government Printing Office), pp. 543–549.
Lefort, J.P., Ben Salmia, A., 1992. Les accretions laurentiennes et al
propagation de l’effet de coin grenvillien. Comptes Rendus de
l’Academie des Sciences Paris 315 (II), 623–627.
Lefort, J.P., Ben Salmia, A., Miller, H.G., 1996. Age and mode of
emplacement of the Collector Anomaly (Canada): is it the
northwestern boundary of Gondwana? Journal of Geodynamics
21, 177–190.
Le Pichon, X., Sibuet, J.C., Francheteau, J., 1977. The fit of the
continents around the North Atlantic Ocean. Tectonophysics 38,
169–209.
Linan, E., Quesada, C., 1990. The Ossa–Morena Zone. Rift
phase (Cambrian). In: Dallmeyer, R.D., Martınez Garcıa, E.
(Eds.), Pre-Mesozoic Geology of Iberia. Springer-Verlag,
Berlin, pp. 259–266.
Lopez Sanchez-Vizcaıno, V., Gomez Pugnaire, M.T., Azor, A.,
Fernandez Soler, J.M., 2003. Phase diagram sections applied to
amphibolites: a case study from the Ossa–Morena/Central
Iberian Variscan suture (Southwestern Iberian Massif). Lithos
68, 1–21.
Mahmood, A., Bennani, A., 1984. S-type characteristics of the
Hercynian granitoids of the Central Palaeozoic Massif,
Morocco. Geological Magazine 121, 301–309.
Martınez Catalan, J.R., Perez Estaun, A., Bastida, F., Pulgar, J.A.,
Marcos, A., 1990. The west Asturian–Leonese zone. Structure.
In: Dallmeyer, R.D., Martınez Garcıa, E. (Eds.), Pre-Mesozoic
Geology of Iberia. Springer-Verlag, Berlin, pp. 103–114.
Martınez Catalan, J.R., Arenas, R., Dıaz Garcıa, F., Rubio
Pascual, F.J., Abati, J., Marquınez, J., 1996. Variscan
exhumation of a subducted Paleozoic continental margin:
the basal units of the Ordenes Complex, Galicia, NW Spain.
Tectonics 15, 106–121.
Martınez Catalan, J.R., Arenas, R., Dıaz Garcıa, F., Abati, J., 1997.
Variscan accretionary complex of northwest Iberia: terrane
correlation and succession of tectonothermal events. Geology
25, 1103–1106.
Martınez Catalan, J.R., Dıaz Garcıa, F., Arenas, R., Abati, J.,
Castineiras, P., Gonzalez Cuadra, P., Gomez Barreiro, J.,
Rubio Pascual, F.J., 2002. Thrust and detachment systems
in the Ordenes Complex (northwestern Spain): implications
for the Variscan–Appalachian geodynamics. In: Martınez
Catalan, J.R., Hatcher, R., Arenas, R., Dıaz Garcıa, F. (Eds.),
Variscan–Appalachian Dynamics: The Building of the Late
Paleozoic Basement. Special Paper-Geological Society of
America, vol. 364, pp. 163–182.
Martınez Catalan, J.R., Arenas, R., Dıaz Garcıa, F., Abati,
J., Sanchez Martınez, S., Fernandez-Suarez, J., 2004.
Zona de Galicia-Tras-Os-Montes. Terrenos e historia acre-
cionaria. In: Vera, J. (Ed.), Geologıa de Espana. SGE-IGME,
Madrid, pp. 162–165.
Matte, Ph., 1986. Tectonics and plate tectonic model for the
Variscan belt of Europe. Tectonophysics 126, 331–334.
Matte, Ph., 1991. Accretionary history and crustal evolution of
the Variscan belt in Western Europe. Tectonophysics 196,
309–337.
Matte, Ph., 2001. The Variscan collage and orogeny (480–290 Ma)
and the tectonic definition of the Armorica microplate: a review.
Terra Nova 13, 122–128.
Matte, Ph., 2002. Variscides between the Appalachians and the
Urals; similarities and differences between Paleozoic sub-
duction and collision belts. In: Martınez Catalan, J.R.,
Hatcher, R., Arenas, R., Dıaz Garcıa, F. (Eds.), Variscan–
Appalachian Dynamics: The Building of the Late Paleozoic
Basement, Special Paper-Geological Society of America,
vol. 364, pp. 239–251.
Matte, Ph., Burg, J.P., 1981. Sutures, thrusts and nappes in
the Variscan arc of western Europe: plate tectonic implica-
tions. In: McClay, K., Price, N.J. (Eds.), Thrust and Nappe
Tectonics, Special Publication-Geological Society of London,
vol. 9, pp. 353–358.
Matte, Ph., Ribeiro, A., 1975. Forme et orientation de l’ellipsoide de
deformation dans la virgation hercynienne de Galicia: relation
avec le plissement et hypotheses sur la genese de l’arc Ibero–
Armoricain. Comptes Rendus de l’Academie des Sciences Paris
280 (D), 2825–2828.
McKerrow, W.S., Mac Niocaill, C., Ahlberg, P.E., Clayton, G.,
Cleal, C.J., Eagar, R.M.C., 2000. The Late Palaeozoic relations
between Gondwana and Laurussia. In: Franke, W., Haak, V.,
Oncken, O., Tanner, D. (Eds.), Orogenic Processes: Quantifica-
tion and Modelling in the Variscan Belt. Special Publication-
Geological Society of London, vol. 179, pp. 9–20.
Murphy, J.B., Fernandez-Suarez, J., Keppie, J.D., Jeffries, T.E.,
2004. Contiguous rather than discrete Paleozoic histories for the
Avalon and Meguma terranes based on detrital zircon data.
Geology 32, 585–588. doi:10.1130/G20351.1.
Neubauer, F., 2002. Evolution of late Neoproterozoic to early
Paleozoic tectonic elements in Central and Southeast European
Alpine mountain belts: review and synthesis. Tectonophysics
352, 87–103.
Neubauer, F., Handler, R., 2000. Variscan Orogeny in the Eastern
Alpine–Mediterranean Mountain belts: how does it relate with
extra-Alpine Variscides? Program and Abstracts of the 15th
International Conference on Basement Tectonics, Galicia 2000,
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198 197
Variscan–Appalachian Dynamics: The Building of the Upper
Paleozoic Basement, A Coruna (Spain), p. 17.
Nys&ther, E., Torsvik, T.H., Feist, R., Walderhaug, H.J., Eide, E.A.,
2002. Ordovician palaeogeography with new palaeomagnetic
data from the Montagne Noir (Southern France). Earth and
Planetary Science Letters 203, 329–341.
Oliveira, J.T., Horn, M., Paproth, E., 1979. Preliminary note on
the stratigraphy of the Baixo Alentejo Flysch Group, Carbon-
iferous of Southern Portugal, and on the palaeogeographic
development, compared to corresponding units in Northwest
Germany. Comunicacoes dos Servicos Geologicos de Portugal
65, 151–168.
Ordonez Casado, B., 1998. Geochronological Studies of the Pre-
Mesozoic Basement of the Iberian Massif: The Ossa–Morena
Zone and the Allochthonous Complexes within the Central
Iberian Zone. PhD thesis, ETH, Zurich. 235 pp.
Ouali, H., Briand, J.L., Bouchardon, P., Capiez, P., 2003. Le
volcanisme cambrien du Maroc central: implications geodyna-
miques. Comptes Rendus. Geoscience 335, 425–433.
Perez Estaun, A., Bastida, F., 1990. The Cantabrian zone. Structure.
In: Dallmeyer, R.D., Martınez Garcıa, E. (Eds.), Pre-Mesozoic
Geology of Iberia. Springer-Verlag, Berlin, pp. 55–69.
Perez Estaun, A., Bastida, F., Martınez Catalan, J.R., Gutierrez
Marco, J.C., Marcos, A., Pulgar, J.A., 1990. The West-Asturian
Leonese zone. Stratigraphy. In: Dallmeyer, R.D., Martınez
Garcıa, E. (Eds.), Pre-Mesozoic Geology of Iberia. Springer-
Verlag, Berlin, pp. 92–102.
Perez Estaun, A., Martınez Catalan, J.R., Bastida, F., 1991. Crustal
thickening and deformation sequence in the footwall to the
suture of the Variscan belt of northwest Spain. Tectonophysics
191, 243–253.
Peucat, J.J., Bossiere, G., 1991. Age U–Pb fini-hercynien de la
ceinture mylonitique de haute pression-haute temperature en
Grande Kabylie (Algerie). Comptes Rendus de l’Academie des
Sciences Paris 313 (II), 1261–1267.
Pique, A., 1979. Evolution structurale d’un segment de la chaine
hercynienne: la Meseta marocaine nord-occidentale. PhD thesis,
Universite de Strasbourg (Sciences Geologiques Memoires) 56.
243 pp.
Pique, A., 1981. Northwestern Africa and the Avalonian plate:
relations during late Precambrian and late Paleozoic time.
Geology 9, 319–322.
Pique, A., 1994. Geologie du Maroc. Marrakech, Pumag. 240 pp.
Pique, A., Michard, A., 1989. Moroccan Hercynides. A synopsis.
The Palaeozoic sedimentary and tectonic evolution at the
northern margin of west Africa. American Journal of Science
289, 286–330.
Pique, A., Jeannette, D., Michard, A., 1980. The Western Meseta
Shear Zone, a major and permanent feature of the Hercynian
belt of Morocco. Journal of Structural Geology 2, 55–61.
Pique, A., Bossiere, G., Bouillin, J.P., Chalouan, A., Hoepffener,
Ch., 1993. Southern margin of the Variscan belt: the north-
western Gondwana mobile zone (eastern Morocco and Northern
Algeria). Geologische Rundschau 82, 432–439.
Pique, A., Bouabdelli, M., Darboux, J.R., 1995. Le rift cambrien du
Maroc occidentale. Comptes Rendus de l’Academie des
Sciences Paris 320 (II), 1017–1024.
Quesada, C., Fonseca, P., Munha, J., Oliveira, J.T., Ribeiro, A.,
1994. The Beja–Acebuches ophiolite (Southern Iberia Variscan
fold belt): geological characterization and geodynamic signifi-
cance. Boletın Geologico y Minero 105, 3–49.
Ribeiro, A., Pereira, E., Severo, L., 1980. Analise da deformacao da
zona de cisalhament Port-Tomar na transversal de Oliveira de
Azemeis. Comunicacoes dos Servicos Geologicos de Portugal
66, 3–9.
Ribeiro, A., Dias, R., Brandao Silva, J., 1995. Genesis of the Ibero–
Armorican arc. Geodinamica Acta 8, 173–184.
Ricou, L.E., 1994. Tethys reconstructed: plates, continental frag-
ments and their boundaries since 260 Ma from Central America
to South-Eastern Asia. Geodinamica Acta 7, 169–218.
Robardet, M., 2002. Alternative approach to the Variscan Belt in
southwestern Europe: pre-orogenic paleobiogeographical con-
straints. In: Martınez Catalan, J.R., Hatcher, R., Arenas, R., Dıaz
Garcıa, F. (Eds.), Variscan–Appalachian Dynamics: The Build-
ing of the Late Paleozoic Basement. Special Paper-Geological
Society of America, vol. 364, pp. 1–15.
Robardet, M., 2003. The Armorica bmicroplateQ: fact or fiction?
Critical review of the concept and contradictory palaeobiogeo-
graphical data. Palaeogeography, Palaeoclimatology, Palaeo-
ecology 195, 125–148.
Robardet, M., Gutierrez Marco, J.C., 1990. Sedimentary and
faunal domains in the Iberian Peninsula during Lower
Paleozoic times. In: Dallmeyer, R.D., Martınez Garcıa, E.
(Eds.), Pre-Mesozoic Geology of Iberia. Springer-Verlag,
Berlin, pp. 385–395.
Robardet, M., Blaise, J., Bouyx, E., Gourvennec, R., Lardeux, H., Le
Herisse, A., Le Menn, J., Melou, M., Paris, F., Plusquellec, Y.,
Poncet, J., Renault, S., Rioult, M., Weyant, M., 1993. Paleo-
geographie de l’Europe occidentale de l’Ordovicien au Devonien.
Bulletin de la Societe Geologique de France 164, 683–695.
Rodgers, J., 1982. The life history of a mountain range. The
Appalachians. In: Hsq, K.J. (Ed.), Mountain Building Processes.
Academic Press, London, pp. 229–241.
Sanchez Carretero, R., Eguiluz, L., Pascual, E., Carracedo, M.,
1990. Part V: Ossa–Morena Zone. In: Dallmeyer, R.D.,
Martınez Garcıa, E. (Eds.), Pre-Mesozoic Geology of Iberia.
Springer-Verlag, Berlin, pp. 292–313.
Sanz de Galdeano, C., Andreo, B., Garcıa-Tortosa, F.J., Lopez-
Garrido, C., 2001. The Triassic palaeogeographic transition
between the Alpujarride and Malaguide complexes. Betic-Rif
Internal Zone (S Spain, N Morocco). Palaeogeography, Palaeo-
climatology, Palaeoecology 167, 157–173.
Sch7fer, H.J., Gebauer, D., Nagler, T.F., 1991. Evidence for Silurianeclogite and granulite facies metamorphism in the Badajoz–
Cordoba Shear belt, SW Spain. Terra Abstracts Supplement 6 to
Terra Nova 3, 11.
Schenk, P.E., 1997. Sequence stratigraphy and provenance on
Gondwana’s margin: the Meguma zone (Cambrian–Devonian)
of Nova Scotia, Canada. Geological Society of America Bulletin
109, 395–409.
Silva, J.B., Oliveira, J.T., Ribeiro, A., 1990. South Portuguese Zone,
structural outline. In: Dallmeyer, R.D., Martınez Garcıa, E.
(Eds.), Pre-Mesozoic Geology of Iberia. Springer-Verlag,
Berlin, pp. 348–362.
J.F. Simancas et al. / Tectonophysics 398 (2005) 181–198198
Simancas, J.F., Martınez Poyatos, D., Exposito, I., Azor, A.,
Gonzalez Lodeiro, F., 2001. The structure of a major suture
zone in the SW Iberian Massif: the Ossa–Morena/Central
Iberian contact. Tectonophysics 332, 295–308.
Simancas, J.F., Exposito Ramos, I., Martınez Poyatos, D.,
Azor, A., Gonzalez Lodeiro, F., 2002. Opposite sub-
duction polarities connected by transform faults in the
Iberian Massif and west-European Variscides. In: Martınez
Catalan, J.R., Hatcher, R., Arenas, R., Dıaz Garcıa, F. (Eds.),
Variscan–Appalachian Dynamics: The Building of the Late
Paleozoic Basement. Special Paper-Geological Society of
America, vol. 364, pp. 253–262.
Simancas, J.F., Carbonell, R., Gonzalez Lodeiro, F., Perez Estaun,
A., Juhlin, C., Ayarza, P., Kashubin, A., Azor, A., Martınez
Poyatos, D., Almodovar, G.R., Pascual, E., Saez, R., Exposito,
I., 2003. Crustal structure of the transpressional Variscan
orogen of SW Iberia: SW Iberia deep seismic reflection
profile (IBERSEIS). Tectonics 22 (6), 1062. doi:10.1029/
2002TC001479.
Suppe, J., 1985. Principles of Structural Geology (Chapter 12).
Prentice Hall, New Jersey.
Tahiri, A., 1991. Le Maroc central septentrional: stratigraphie,
sedimentologie et tectonique du PaleozoRque; un exemple de
passage des zones internes aux zones externes de la chaıne
hercynienne du Maroc. PhD thesis, Universite de Bretagne
occidentale, Brest. 311 pp.
Tahiri, A., 1994. Tectonique hercynienne de l’anticlinorium
de Khouribga-Oulmes et du synclinorium de Fourhal.
Geologie du Paleozoique du Maroc central et de la Meseta
orientale, Bulletin de l’Institut Scientifique (Rabat) Numero
Special, vol. 18, pp. 125–144.
Tait, J.A., Bachtadse, V., Franke, W., Soffel, H.C., 1997. Geo-
dynamic evolution of the European Variscan fold belt: palaeo-
magnetic and geological constraints. Geologische Rundschau
86, 585–598.
Tapponier, P., Peltzer, G., Le Dain, A.Y., Armijo, R., Cobbing,
P., 1982. Propagating extrusion tectonics in Asia: new
insights from simple experiments with plasticene. Geology
10, 611–616.
Torsvik, T.H., Smethurst, M.A., Briden, J.C., Sturt, B.A., 1990. A
review of Palaeozoic palaeomagnetic data from Europe and their
palaeogeographic implications. In: McKerrow, W.S., Scotese,
C.R. (Eds.), Palaeogeography and Biogeography. Special
Publication-Geological Society of London, vol. 12, pp. 25–41.
Truyols, J., Arbizu, M.A., Garcıa Alcalde, J.L., Garcıa Lopez, S.,
Mendez Bedia, I., Soto, F., Truyols Massoni, M., 1990. The
Asturian–Leonese domain (Cantabrian Zone). In: Dallmeyer,
R.D., Martınez Garcıa, E. (Eds.), Pre-Mesozoic Geology of
Iberia. Springer-Verlag, Berlin, pp. 10–19.
Vauchez, A., 1975. Tectoniques tangentielles superposees dans le
segment hercynien Sud-Iberique: Les nappes et plis couches de
la region d’Alconchel–Fregenal de la Sierra (Badajoz). Boletın
Geologico y Minero 86, 573–580.
Vegas, R., Medialdea, T., Munoz, M., Dıaz del Rio, V., Somoza, L.,
2004. Nature and tectonic setting of the Guadalquivir Bank
(Gulf of Cadiz, SW Iberian Peninsula). Revista de la Sociedad
Geologica de Espana 17, 49–60.
Weil, A.O., Van der Voo, R., van der Plujim, B.A., 2001.
Oroclinal bending and evidence against the Pangea mega-
shear: the Cantabria–Asturias arc (northern Spain). Geology
29, 991–994.
Winchester, J.A., The PACE TMR Network Team, 2002. Palaeozoic
amalgamation of Central Europe: new results from recent
geological and geophysical investigations. Tectonophysics
360, 5–21.
Zahraoui, M., 1994. Le Silurian. Le Devonian inferieur et moyen.
Geologie du Paleozoique du Maroc central et de la Meseta
orientale, Bulletin de l’Institut Scientifique (Rabat) Numero
Special, vol. 18, pp. 38–56.